Butanediol production processes often include a two-step process. For example, such processes may include contacting an allyl alcohol stream with a hydroformylation catalyst in the presence of a gas stream to form an intermediate and hydrogenating the intermediate in the presence of a hydrogenation catalyst to form butanediol. Crude (i.e., unpurified) allyl alcohol streams may contain an appreciable level of impurities. Such impurities may be separated from the allyl alcohol prior to use in subsequent processes, such as butanediol production processes. However, the impurities can be difficult to separate from the allyl alcohol itself.